Apparatus for crushing or grinding ore



Feb. '6, 1940. J, w, BELL 2,189,441

APPARATUS FOR CRUSHING OR GRINDING ORE Fi'led Sept. 15, 1936 2Sheets-Sheet 1 4/ 34549 ass Feb. 6, 1940. J. w. BELL APPARATUS FORCRUSHING OR GRINDING ORE Filed Sept. 15, 1936 2 Sheets-Sheet 2 Invenior:

2'7 06 2 M MM Patented Feb. 6, 1940 l K PATENT OFFICE APPARATUS FORCRUSHING OR GRINDING ORE John W. Bell, Montreal, Quebec, CanadaApplication September 15, 1936, Serial No. 100,891

9 Claims.

I This invention relates to methods of and apparatus for crushing orgrinding ore, rock and other materials, and more particularly to methodsand apparatus in which the crushing or grinding ac-' tion is effected inwhole or in part by the direct pressure of a crushing agency appliedthrough centrifugal force.

I The invention has among other objects the utilization of a controlledcrushing pressure in grinding operations, the establishment andmaintenance of a thin, even flow of the materials to be crushed. acrossthe face ofa crushing agency, and

the utilization in conjunction with direct pressure also of a shearingaction on the materials to be .cruushcd or ground. These and otherobjects of the invention will be best understood by the followingdescription when taken in connection with the accompanying illustrationof one specific embodiment thereof, while its scope will be moreparticularly pointed out in the appended claims.

In the drawings: Fig. 1 is an elevation, in partial section and partlybroken away, showing the principal work-- form of the invention; andFig. 2is a fragmentary plan showing certain parts illustrated in Fig. 1.

Referring to the drawings and to the embodiment of the inventionsubmitted for illustrative purposes, the ore crushing machine comprisesa frame-work designated generally by the numeral l on which is supportedthe large annular ring die 3, against the inner face of which the oreis.

to be crushed. The frame also provides journaling support for theupright driving shaft ,5 positioned concentrically with relation to thering die and carrying one or more crushing rollers 1 (herein, by way ofexample, eight in number) of substantial mass.

5 force for" crushing the ore as the latter is fed between the innerface of the ring and the outer faces of the rollers.

Referring first to the ring die 3, the latter is in the form of acontinuous-annular ring of feeing parts of a crushingmachine embodyingone Each roller is freely and individually rotatable about an uprightaxis and is tangular cross section having its outer face abuttingagainst the inner face of a retainer ring 9 and resting on a small sillor shoulder ll presented by the retainer ring and clamped to the latterby the overlying clamping lugs l3. The retainer ring is constructed ofslightly spaced segments (see Fig. 2) united by bolts 15, which latter,when tightened, lock the ring die fast in its retainer ring. Theretainer ring rests on a bed plate ll where it is held against lateralmovement by three centering screws l9 (one of which only is shown inFig. 1) When the ring die is installed in the retainer ring it isbrought into concentric relation to the axis of the driving shaft 5 bymeans of the centering screws l9, after which the retainer ring isbolted to the bed plate by stud bolts 21 which pass through the retainerring with sufficient clearance to permit the centering adjustmentreferred to.

To rotate the rollers through their orbital path there is provided thedriving motor 23 adapted to drive the driving shaft 5 through thebeveled.

' pinion 25 and beveled gear 21, the latter keyed to the shaft by thekey 29. Secured to the shaft to rotate therewith is the supportingstructure or table 31 which serves as a support for the crusher rollersI, together with their journals and guides and various other parts ofthe apparatus, including those for controlling and regulating thecentrifugal crushing pressure developed by the rotation of the planetarystructure of which the rollers form a part.

Each crushing roller comprises the hardened steel outer ring ortire-like member shrunk on a ring core 33 which in turn is clamped bybolts 35 between upper and lower plates 31 and 39. Carried by therespective upper and lower plates are short stud shafts 4i journaled torotate freely in bearings, preferably of the roller type, the upperbearing 43 with its stud shaft only being shown (Fig. 1). These bearingsare carried by upper and lower plates 45 and 41, respectively, the lowerplate having upright side members terminating in top flanges to whichthe upper plate is bolted, the three parts 45, 41 and 49 constituting abox-like carriage in which the crushing roller is journaled and carried.This carriage rests through the lower plate 41 on the supporting table3| and is guided thereon for a radially outward and inward movement bymeans of gibs 5| secured to the table, so that, as regulated by thecontrollingdevices to be described, when the supporting platform isrotated, the rollers may move simultaneously outward in a radial butstraight line direction with relation to the ring die toeifect ringaction, the described conlicated for each roller of the ment corn; isingfront plate or head 51', the edges of the nt plate clearing thesurrounding walls of the spring cage and permitting movement of thlatter with relation to the front plate. The front ate is fixed inposition on the end of the tension rod 5& by the adjusting nut 6| andlocking nut the rod, except for the adjustment herein c ccribed, beingalso fixed and the result being that 'ne front abutting plate 51 for thespring occupies a definitely fixed position with relation to the axis ofthe machine.

The spring when installed is preferably placed under compression with adefinite force (one ton, by way of example) and is maintained in thiscondition when the mechanism is at rest by means of four bolts 65, theends of which pass loosely through the back plate with their headsseated there agains but are fixedly threaded into the front plate 57?and there held by the lock nuts 67.

The result is that normally when the machine is at rest, while theroller carriage is held by the bolts 65 at a fixed position radiallywith relation to the ring die, which position depends on the position ofthe tension rod 59 and on the degree of compression of the spring, thecarriage may move radially outward when the centrifugal force, underoperation of the machine, becomes sufficient to further compress thespring, the back plate 55 with the ca; iage moving freely over the boltsand relatively to the fixed abutting plate 5?.

The method of establishing and maintaining a definite centrifugalcrushing force will now be clear by the aid of an illustrated numericalexample. If it is assumed that the roller and its carriage, due to theirmasses, the distances of their centers of gravity from the central axisof the machine and the rate of speed of rotation of the shaft, willdevelop a centrifugal force of seven tons, and further that the spring53 under this force will compress of an inch, if the rollers when atrest are so adjusted by the tension rod and the initial compression ofthe spring 53 as to clear the face of a truly concentric ring die by ofan inch, then, when the shaft reaches its rated speed, the centrifugalforce becomes absorbed by compression of the spring, the rolls will justgraze the vertical faces of the ring die and the force applied to thelatter will be zero in magnitude. If, however, all of the carriages forthe eight rollers are moved out radially of an inch, as by theadjustment of the tension rod, the spring will then compress of an inch,absorbing six tons of the centrifugal force and the remaining componentof one ton is exerted by each roller against the ring die. Obviously byadvancing or retracting the rollers radially, any force from the maximumof seven tons down to zero may be established at the crushing surfacesand maintained definitely so long as the speed of rotation is maintainedat a constant rate but a part of the centrifugal force developed willalways be absorbed in the spring as spring compression when the machineis in operation in order to preserve even wear of the rollers and ringdie. In the case of each roller carriage, when the machine is inoperation, the carriage moves radially outward and compresses the springuntil the centrifugal force is in equilibrium with the total counterpressure comprising spring pressure plus the pressure against the ringdie.

To provide for the adjustment of the effective crushing force, means areembodied for simultaneously moving each tension rod radially and therebyadjusting the static or normal position of each roller carriage, suchmeans being operable during the rotation of the machine.

For this purpose each tension rod 59 extends radially inward andterminates in a portion which passes through and has threaded engagementwith the threaded bore of a worm gear 69, the several worm gears beingjournaled in the wall ll of a drum-like structure which is fixedlysecured to the supporting table 3|. Each worm gear 59 serves as amechanically actuated nut, which, when turned, adjustably moves thecarriage and its roller outwardly or inwardly.

Each pair of adjusting worm gears (Fig. 2) is in engagement with avertically positioned worm shaft 73. The upper end of each of theseveral worm shafts, herein four in number (see Fig. 2), carries a spurgear 75, which gears are symmetrically disposed about and meshed with acentral spur pinion 'i'l concentric with the driving shaft 5.

If, therefore, the pinion I! is turned relatively to the shaft 5, theseveral worm gears 69 are each rotated through gears '15 and worm shaftsl3, and the several tension rods are simultaneously moved radially inone direction or the other, thereby shifting the roller carriage androllers with relation to the ring die. Since each worm shaft 73 turnsone worm gear clockwise and the other counterclockwise, their respectivetension rods are provided with right-hand and left-hand threads,respectively, so that all roller carriages are moved in the samedirection and to an equal extent for any movement of the pinion I! withrelation to the shaft 5.

The pinion ll is fixedly secured to an elongated sleeve 19 which fitstelescopically over the upper end of the central drive shaft 5, theupper end of the sleeve terminating in a shaft on which is secured abrake-drum 83. The latter is encircled by a brake-band 85 which, throughthe hand wheel 8'! and shaft 89, may be caused to apply at will adelicately graduated friction to the brakedrum to more or less retardits movement.

The frictional fit of the sleeve 19 over the shaft 5 is such that whenthe machine is in normal operation and when the brake-drum is freed fromthe brake-band, the sleeve rotates with and at the same speed as theshaft, the pinion '11 thereupon turning with the shaft and with theentire rotating structure and having no effect on the radial position ofthe tension rods. The fit of the sleeve 75 on the shaft 5, however, isalso such that when the shaft 5 is being rotated, the movement of thesleeve may be slightly checked and retarded relatively to the shaft byapplying the brake-band so that the shaft will then turn relatively tothe pinion and effect a longitudinal movement of the tension rods. Theconnections are such that a slowing down of the sleeve with relation tothe movement of the shaft effects a radially outward movement of thetension rods. This provides an ore crushing machine in which thecrushing pressure may be regulated at will within close and minutegradations to suit the requirements of any particular ore, rock or othermaterial to be crushed. This will be best understood by a numericalexample, submitted solely for" illustrative purposes and explaining one7 method of adjusting the machine to provide the required crushingpressure.

Let it be assumed, by way of illustration, that the most economicalgrinding pressure for a given ore or other material is one ton and thatthe centrifugal force developed at each roller at the rated speed of themachine is seven tons and that such force will compress the springs 53each of an inch. The rollers would then be adjusted so that with themachine at rest each roller is exactly of an inch away from the face ofthe ring die. Such adjustment may be made in the first instance by theadjusting and locking nuts Bi and 63 on the endof the tension rods.

In practice the machine is preferably equipped with an ammeter 9iregistering the current consumption of the driving motor 23. Previoustests will have established the particular reading of the motor ammetercorresponding to the most economical grinding pressure for a given classof material at a given rate of feed and at the rated speed of themachine, which pressure in the above example has been assumed tobe oneton. The machine having been brought up to speed, the

brake-band is then applied to the brake-drum 83 with a suificientpressure to slightly retard the movement of the sleeve 19 with relationto the shaft 5, such retardation being maintained until the checkedmovement of the pinion T! and the resulting outward movement of theroller carriages and rollers produce the desired pressure, which will beindicated by the reading on the motor ammeter. The brake-band is thenfreed from engagement with the drum.

If it be assumed that the main shaft 5 normally turns at a speed ofrevolutions per minute and the brake-drum and its attached sleeve andpinion are slowed down to 99 revolutions per minute, the gearinginterposed between the tension rod and the pinion may be readilyproportioned so that the outward movement of the rollers in the entireperiod of one minute would amount to no more than 7 of an inch. It willtherefore be seen that this mechanism permits an extremely minuteregulation of crushing pressure and at the same time a regulation Withinwide limits from zero. to maximum.

As the ring die and roller surfaces wear the crushing pressure drops.This is accompanied by a corresponding drop in the power consumptionwhich will be indicated by the motor ammeter reading. It is then merelynecessary to apply sufiicient brake pressure to advance the rollers thedistance required to again raise the current reading on the ammeter to apoint corresponding to a one ton roller pressure.

A marked advantage secured by the use of a controlled crushing pressurelies in securing an even wear of the ring die and of the roller tires.In machines of the prior art utilizing centrifugal crushing pressure andwhere the latter has been uncontrolled, any localized Wear tends toproduce a rapidily increasing flattened face so that the ring die androller tires are required to be frequently removed from the machine andreshaped or trued up in a lathe. Such parts, therefore, not only requirefrequent removal and reshaping but are relatively short lived. In thecrushing. machine hereindescribed, however, the

control of the centrifugal crushing force acts automatically toestablish and maintain true circular contacting surfaces in both therollers and the ring die. For illustration, taking the previous example,where the crushing force has been ad-' justed for one ton, if the innerface of the ring dieis or becomes at any time other than truly circularin form, and if for instance it presents a section the inside of whichprojects inwardly {a of an inch beyond the limits of a true circle, thenwhen any roller reaches this projection it automatically applies acrushing force of two tons, thereby producing a rapid wear which sooncorrects that irregularity. Conversely, if the ring die has a concavesection of an inch deep, the crushing action on such section becomeszero. The result is that approximately true circular surfaces aremaintained on both the ring die and rollers, the grinding pressure beingautomatically altered to correct any deviation from that condition. Withthis condition established and maintained, the grinding pressure willremain approximately uniform and the grinding surfaces protected againstuneven wear. This serves to reduce the wastage or wear of metal in thedie and rollers and to reduce overgrinding, unnecessary powerconsumption, and cost of crushing per ton.

Referring now to the means for effecting feed of the materials to thecrushing agencies, such material, whether in the form of dry solids orsolids With water and constituting pulp, are delivered to and caused topass down the inclined trough or feed launder 93 to the stationary feedbox 95, which latter comprises a drum encircling the sleeve 19 andcarried at the end of the trough 93. Within the feed box there areprovided one or more lugs or arms 91 secured to and rotatable with thesleeve 19. Such lugs serve to stir and distribute the materials andcause them to pass down through a narrow annular slot-like orifice 99 inthe bottom of the feed box and concentric with and closely surroundingthe sleeve '19.

Beneath the feed box and secured to the sleeve 19 to rotate therewith isa centrifugal revolving feed plate lill in the form of a flat disk, theperipheral edges of which terminate just short of the surroundingcylindrical casing I03 resting on the retainer ring 9 so as to leave anannular opening at the periphery of the feed plate. The materials aredelivered through the annular orifice 99 in the feed box to the feedplate itl in the form of a uniformly distributed annulus beneath theorifice. The centrifugal force developed by the revolving feed platecauses this accumulation of material to advance radially outward,separating and spreading evenly over the entire surface of the plate andbeing discharged therefrom evenly and uniformly over its peripheraledges. Beneath the edge of the feed plate thematerial so advanced isallowed to pile up on the ring die, as indicated in Fig. 1, until theangle of repose is reached, When further accession to theaccurnulationfrom the feed plate causes the materials to flow down overthe inner face of the ring die in a thin stream, evenly distributedaround the ring die face and of a substantially uniform thick mass orbody. This permits the crushing rollers to exert each its crushing forceon individual particles with a minimum of cushioning effect and securesa maximum efficiency in the application of such crushing force.

In machines of the prior art it has been common practice to concentratemore or less the delivery of the materials at some point or position inthe path of the crushing rollers themselves so that the rollers andscrapers are relied on to distribute such materials and carry themaround the ring die. This is not only wasteful of power in maintainingthe rotation of the mass of pulp, but also prevents the effectiveapplication of the crushing force due to the cushioning effect ofrelatively thick masses of pulp between the ring die and the crushingfaces of the rollers.

The material crushed between the ring die and the rollers drops into anunderlying stationary annular hopper I95, the walls of which aredownwardly and inwardly inclined to provide an annular trough at itsbottom having a discharge opening I0? at some point in the apex of thetrough immediately above a downwardly and outwardly inclined troughI051. The crushed material gravitating to the bottom of the hopper iscarried around the bottom trough thereof and discharged through theopening IB'I by means of stirring members I II depending from the bottomof the rotary table 3| or by means of air currents developed by therotating parts, or in part by both means.

From the trough I09 the crushed materials pass through an opening H3 atthe side of the machine, whence they may be conveyed by suitable means,such as a centrifugal pump or air lift (not shown), to a classifier ofany usual construction arranged in a closed circuit with the describedgrinding machine, the materials of the required degree of finenessoverflowing and being withdrawn from the classifier and the coarsermaterials requiring further grinding being returned to the feed troughof the crushing machine. Such provisions are well known and they are notherein illustrated.

Means are also herein provided to add to the crushing or grinding effectproduced by direct pressure against the materials and herein securethrough the centrifugally actuated rollers also an additional shearingor rubbing action. In the illustrated embodiment of the invention thisis accomplished by causing the rollers, while pressed against androlling over the particles of material flowing down the vertical face ofthe ring die, to so move relatively to the ring die as to exert also africtional rubbing or shearing action on such particles. Such shearingaction may be desirable in certain cases where finer grinding isrequired.

The shearing action is herein secured by causing the drive shaft 5during its rotation, together with the supporting platform 3I and partssecured thereto, to be periodically raised and lowered thereby causingeach roller to be slightly raised or lowered during its travel aroundthe inside face of the ring die, with the result that an additionalamount of crushing is produced by the vertical sliding action of onecrushing face over the other.

While hydraulic or various other devices may be employed for securingthe vertical reciprocatory movement of the roller carriages, herein theshaft 5 is periodically raised and lowered to a slight extent by theoperation of an eccentric H5 and eccentric drive shaft operativelyrelated to the bottom of the shaft 5 and driven when desired from therotary movement of the shaft itself.

For this purpose the lower end of the shaft 5 is mounted in a thrust orstep bearing II! and is additionally journaled in a radial bearing II9,

this hearing being contained in a bearing box IZI which is adapted tohave a sliding up and down movement in a bearing I23 in the machineframe but is prevented from turning by a key and slot connection 425.

An upper radial bearing I21 for the drive shaft 5 is similarly containedin the bearing box I29, being adapted for sliding up and down movementin a bearing 3| in the machine frame but prevented from turning by thekey and slot connection I33.

To periodically raise and lower the shaft, the bearing box I2! at thebottom of the drive shaft is connected to an eccentric strap or link I35operatively related to the eccentric II5 so that, as the latter isturned, the shaft is slowly raised and lowered.

To turn the eccentric a pinion I3! is fixedly secured on the shaft 5 andmeshes with a gear I39 which in turn drives a vertical worm shaft MI Theworm shaft I4I engages with the worm gear I43 mounted on a shaft whichis adapted to be clutched to and unclutched from the eccentric II5 bymeans of a clutch indicated conventionally at I45. When the clutch isthrown in, the eccentric acts periodically to raise or lower the driveshaft, carrying with it the supporting table 3|, the rollers, rollercarriages and connected parts, the feed plate IUI, sleeve I9 and brakedrum 83, and in fact the entire rotating structure. Relative verticalmovement between the shaft and the bevel driving gear 2'! is permittedby the key and slot connection I41. The desired shearing effect may besecured by a relatively slight up and down movement of the shaft andthis may be confined to an amount representing a fractional part of theWidth of the inner ring face of the die so that the rollers in theiruppermost position will overlap somewhat the upper edge of the ring dieand in their lowermost position will slightly overlap the bottom edge.

In many cases where fine grinding by the shearing action is unnecessaryto the purpose for which the material is required, the resulting rubbingor shearing action would merely increase the Wear on the ring die androller tires and the grinding cost per ton. The formation of thinprojections on the ring die or rollers, due to slight difference inwidth, may be avoided by raising the shaft bearing box I2! and theremaintaining it so that the rollers are caused to rotate for a givenperiod while overlapping slightly the upper edge of the ring die andthen subsequently lowering the shaft bearing box and there maintainingit so that the rollers are then caused to rotate while overlappingslightly the lower edge of the ring die, the direct centrifugallyactuated pressure of the rollers only being relied on in each casewithout any shearing or rubbing action. Such positions of the driveshaft may be established and maintained by turning and locking theeccentric while unclutched from the drive shaft, or for the eccentricthere may be substituted other means such as a mechanical or hydraulicjack.

While I have herein shown and described for the purposes of illustrationone specific embodiment of the invention, it is to be understood thatextensive deviations may be made therefrom in the form, construction andrelative arrangement of parts, all without departing from the spirit ofthe invention.

I claim:

1. In a machine for crushing ore or other mahaving a surface 'on whichthe materials to be crushed are presented, crushing means comprising aplurality of tcentrifugally actuated crushing rollers movable radiallyoutward under centrifugal force, means for carrying said crushingrollers in an'orbital path in cooperative relation to the annularmember, connections for the several rollers comprisinga spring for each,the springs for the severalrollers being initially compressed under asimilar compression in the static position of the carrying means,..thespring for each roller being capable at 'normalsp'eed of absorbing bycor. pression all of the'centrifugal force developed by the roller,amember for each roller having a fixed position'in the normal operationof the machine, and means to simultaneously adjust said members for thedifferent rollers to riadally advance the static position of each rollertoward the'annular member until contact is had therewith, and to furtheradjust said members until each reaches its said normal fixed position; I'2. In a machine for crushing ore or like materials, the coinbinationwith an annular ring die of a rotatable supporting structurerotatableabout an axis concentric with said ring die, crushing means comprising aroller and roller support movably supported on said structure andmovable outwardly under centrifugal force, a compression springinterposed between the structure and the roller support to resistcentrifugal force, a first abutment acting against one end of the springand having a position during the normal operation of the machineunaffected by outward centrifugally enforced movement of the rollersupport, a second abutment acting against the opposite end of the springsecured to and movable with the roller support to compress the spring,and means to adjust the radial position of said first abutment outwardlywhile the machine is in running operation, thereby to move the rollersupport until the roller has grazing contact with the ring die and onfurther outward adjustment to relax the spring to increase the crushingforce at the ring die. i

3. In a machine for crushing ore or like materials, the combination withan annular ring die of a rotatable supporting structure rotatable aboutan axis concentric with said ring die, crushing means comprising aroller and a roller support supported on said structure and movableoutwardly under centrifugal force, a spring the deformation of whichresists centrifugal force located between-the structure and the rollersupport, a member secured to and movable with the roller support andhaving operative connection with one end of the spring and having apostion during the normal operation of the machine unaffected by outwardcentrifugally enforced movement of the roller support, an opposite endof the spring having operative connection to the outwardly movableroller support, and means to adjust the radial position of said memberoutwardly while the machine is in running operation, thereby to move theroller support and spring bodily outward until the roller has grazingcontact with the ring die and on further outward adjustment to relax thespring to increase the crushing force at the ring die.

4. In a machine for crushing ore or other materials the combination withan annular member having a surface on which the materials to be crushedare presented, of crushing means comprising a plurality of centrifugallyactuated crushing rollers each with its roller support, the

said plurality of rollers and roller supports being movable radiallyoutward under centrifugal force independently of each other, means forcarrying said crushing rollers in an orbital path in operative relationto the annular member, a separate spring for each roller, meansoperatively mounting each spring between its respective roller androller support to absorb a part of the centrifugal force under whichsaidrollers are urged toward the annular member, and an adjustableconnecting member for each of said springsadjustable during the runningoperation of the machine to simultaneously adjust the crushing pressureof the rollers for any given rate of rotation of the machine. I

5. In a machine for'crushing ore or other materials the combination withan annular member having a surface on which the materials to be crushedare presented, of crushing means comprising a plurality of centrifugallyactuated crushing rollers each with its roller support, the saidplurality of rollers andjroller supportsbeing movable radially outwardunder centrifugal force independently'of each other,-means for carryingsaid crushing rollers in an orbital path in operative relation to theannular member, separate resilient means between each of said rollersand its respective roller support for absorbing a part of thecentrifugal force under which each roller is urged toward the annularmember and adjustable means operable during the running operation of themachine for varying the amount of centrifugal force absorbed by theresilient means.

6. In a machine for the fine crushing of ore, or other materials, thecombination with a ring die of a horizontal supporting structurerotatable about an axis concentric with said ring die, a

plurality of crushing members carried by saidv structure in an orbitalpath concentric with said ring die, each comprising a crushing rollerro-tata-. ble on its own axis mounted on a roller carriage which in turnis mounted on the horizontal supporting structure, the carriage andcrushing roller being movable outward as a unit horizontally under theurge of centrifugal force, a spring in which all effective centrifugalforce generated by the mass and velocity of the roller and rollercarriage is balanced, adjustable means in connection with said springandoperative while the machine is running to, move the roller andcarriage outward first until the roller makes grazing contact with thering die, and then further to move said roller and carriage 'to releaseany fraction of the centrifugal force balanced in the spring whereby thesame is applied as crushing force on the face of the ring die and thefraction of the whole centrifugal force selected as the most efficientcrushing force'for a given ore may be applied and maintained. i

'7. In a machine for the fine crushing of ore or other materials, thecombination with a ring die of a horizontal supporting structurerotatable about an axis concentric with said ring die, a plurality ofcrushing members carried by said structure in an orbital path concentricwith said ringdie, each comprising a crushing roller rotatable on itsown axis mounted on a roller carriage which in turn is mounted on thehorizontal supporting structure, the carriage and crushing roller beingmovable outward as a unit horizontally and radially under the urge ofcentrifugal force along a fixed and unchanging radius drawn from thecenter of the ring die through the center of the roller, a spring, inwhich all effective centrifugal force generated by the mass and velocityof the roller and roller carriage is balanced, adjustable means inconnection with said spring and operative while the machine is runningto move the roller and carriage radially outward first until the rollermakes grazing contact with the ring die, and then further to move saidroller and carriage to release any fraction of the centrifugal forcebalanced in the, spring whereby the same is applied as crushing force onthe face of the ring die and the fraction of the whole centrifugal forceselected as the most efficient crushing force for a given ore may beapplied and maintained.

8. In a machine for crushing ore or other materials, the combinationwith an annular ring die, of a cooperative, radially and outwardlymovable, centrifugally acuated, crushing roller, a rotatable supportingstructure for said roller for carrying it through an orbital path inoperative relation to the ring die, a spring the deformation of whichresists centrifugal force and limits the outward movement and crushingforce of the roller, said spring constituting a part of the connectionbe tween said roller and said carrying means, spring relaxing meansoperative when the roller is in contact with the ring die for releasingthe spring to augment the centrifugal force developed as crushing forceby the roller, and means for adjusting said relaxing means including adevice mounted concentrically with the axis of rotation of saidstructure and operative while the machine is running.

9. In a machine for crushing ore or other materials, the combinationwith an annular member having a surface on which the materials to becrushed are presented, of crushing means comprising a plurality ofcentrifugally actuated crushing rollers each with its roller support, arotatable structure carrying said roller supports, said plurality ofrollers and roller supports being movable radially outward undercentrifugal force independently of each other, separate resilient meansbetween each of said rollers and its respective roller support forabsorbing a part of the centrifugal force under which each roller isurged toward the annular member, means for adjusting said resilientmeans for varying the amount of centrifugal force absorbed thereby, andcontrolling means including a member mounted concentrically with theaxis of rotation of said structure and operable during the running ofthe machine to simultaneously adjust each of said resilient. means.

JOHN W. BELL.

